I have several military rifles and for some of them, I have to make brass from another caliber. I have found that for really tough sizing problems, the Lee Case Lube is, for me anyway, the best. It seems to lubricate better than Hornady One Shot, although it is not as easy to apply (I rub it on with my fingers). It is water-soluable so you can just wipe your brass off with a damp cloth when you are done. I generally use a cloth dampened with WD40 - No, it doesn't kill the primers and it removes the lube and protects the case from corrosion.
As a side note, I have used WD40 for years and I can't see what is so bad about it. I love the stuff and it has always done a great job for whatever tasks I have used it for.
Steve